Creating Pricing Groups

Making a POST call to /api/PriceSheetGroup/ returns back a required PriceSheetId

If I attempt to POST to /api/PriceSheet/ I get back a 500 error. Below is a sample body request.

{
                "$type": "Asi.Soa.Commerce.DataContracts.PriceSheetData, Asi.Contracts",
                "PriceSheetGroups": {
                    "$type": "Asi.Soa.Commerce.DataContracts.PriceSheetGroupDataCollection, Asi.Contracts",
                    "$values": [
                        {
                            "$type": "Asi.Soa.Commerce.DataContracts.PriceSheetGroupData, Asi.Contracts",
                            "Group": {
                                "$type": "Asi.Soa.Membership.DataContracts.GroupSummaryData, Asi.Contracts",
                                "GroupId": "CHAPT/EAST"
                            }
                        }
                    ]
                },
                "Description": "Product grouping price",
                "Name": "Test Pricing 3",
                "PriceCustomerType": "3"
            }

Works fine if I do a PUT with PriceSheetId but can't seem to create a new price sheet. Any special trick to this?

Tested on 20.3.180.315